Compensating mechanism for concrete-pipe machines



Nov.8,1927. 1,648,788

v 8 C. P. STEWART COMPENSATING MECHANISM FOR CONCRETE PIPE MACHINES Filed Dec. 22, 1926 a0 v gyvwzw foc I,

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2/ awm k w Patented Nov. 8, 1927.

CHARLES P. STEWART, OF PEE DEE, NORTH CAROLINA.

COMPEKSATING MECHANISM FOR CUNORETE-IPTPE MACHINES.

Application filed December 22, 1926. Serial No. 156,419.

This invention relates to compensating mechanism for concrete pipe machines. In a known concrete pipe machine, already on the market, the packer head, which carries the forming wings and trowel, is given an up and down movement, during ts rotation, through the medium of a pivoted beam, a rotative gear and a connectlng rod, pivoted to the gear and to the beam. However, the arrangement -described, results in imparting an upward movement to the packer shaft and head that 1s not uni orm throughout the stroke and it is the ob ect of the present invention to provide, in the known type of machine referred to, a compensating mechanism for beam of the packer shaft, which will result in imparting uniform upward movementto said packer shaft.

Under the construction of the old method, the excessively slow movement of the packer head as it approached the top of its stroke, tended to pack the pipe too hard, caused excessive wear on the wings and trowel of the packer head and frequently stalled the machine, resulting in considerable delay in getting it started again.

Further objects and advantages Wlll be set forth in the detailed description which follows.

In the accompanying drawing:

Fig. 1 is a diagrammatic side view of a compensating mechanism constructed in accordance with the present invention.

Fig. 9. is a diagrammatic view showing the relative movements of the several parts; and

Fig. 3 is a detail view of the packer shaft and head.

Like numerals designate correspomling parts in all of the figures of the drawing.

Referring to the drawing, 5 designates the supporting frame of a. concrete pipe machine, and G, a gear mounted for rotation upon said frame. A. connecting rod 7 is pivoted to the gear at 8 and is pivotec at 9 to an extension 10 of a beam 11. It is clear that rotation of the gear will result in imparting an up and down movement to the beam 11. A slotted portion 12 of this beam (which may be, and, in practice, is bifurcated) engages pins 13, which project from a sleeve 14, that is mounted between collars 14 and 14 of the packer shaft 15. The packer shaft is caused to rotate during its vertical reciprocation through the methe actuating packer head 19 upon the lower end of the packer haft, carries packer wings 20, which act radially or circumferentially of the packer head to press the concrete outwardly against the sides of a mold (not shown) during the upward travel of the said head. At the same time a trowel 21 upon the under side of the packer head, smooths out any ridges left by the wings and leaves the pipe true to size and smooth inside.

The parts so far described are of a usual and known construction and constitute no part of the present invention, except as they may enter into combination therewith. It is clear that if the rear end of the beam 11 were supported upon a fixed pivot, the motion imparted to the packer shaft would be a nonuniform one. That is, the packer shaft would move faster during the midstroke of the connecting rod 7 than during the time that the connecting rod is passing over the top and bottom centers.

According to one embodiment of my invention, I mount upon the drive shaft 22 of the gear 8, a sprocket Wheel 28 which drives through. the medium of a sprocket chain 24 to a sprocket wheel 25, which has one half the number of teeth that the sprocket wheel 23 has. Thus the sprocket wheel 25 will rotate twice as fast as the sprocket wheel 25 and gear 6. An eccentric 26 upon the shaft 27' of the sprocket wheel 2:, actuates an eccentric rod 28. This eccentric rod has pivotal engagement at 29 with a guide link 30. This guide link is pivoted at 31 upon a supporting bracket 32 that is carried by a member of the frame 5. The pivot or fulcrum of the beam 11 is located at 32 upon a pin which traverses bot-h guide link and beam. However, the pivot 29 does not traverse the beam but merely forms a pivotal connection between guide link and connecting rod 28. Thus the connecting rod will act to so shift the guide link and the fulcrum 82 carried there by, as to compensate for the varying rates of travel of connecting rod 7, with the result that a uniform motion will be imparted to the packer shaft. The manner in which this is accomplished will be apparent from an inspection of Fig. 2.

machine and run through again.

By the addition of my invention to a concrete pipe machine of the character indicated, marked improvements and economies in manufacture have been efl'ected, because, with the old construction, the tendency has been to pack the pipe too hard at each end and not hard enough in the middle. Since a very dry mixture is used in the manufacture of the pipe, the result of not having them packed hard enough in the middle has been that when the jacket or mold is removed many of the pipes collapse and the material has to be gathered up and returned to the The device of the present invention has entirely overcome these objections, makes a better and more uniform pipe and greatlyincreases the output of the machine, because of the elimination of delays heretofore encountered.

It is to be understood that the invention is not limited to the precise arrangement shown. because it is manifest that various n'iechanical expedients might be resorted to to bring about the compensating action. F or example, the use of a crank in the place of the eccentric, or a cam and roller in the place of the eccentric would accomplish the same result. Therefore it is to be understood that the invention includes within its purview whatever changes fairly come within either the terms or the spirit of the appended claims.

Having described claim is:

1. In a concrete pipe machine, the combination with a rotative packer head and my invention what I shaft, a pivoted beam engaged with said shaft for imparting up and down movement to said shaft and means for shifting the fulcrum of said beam to maintain a uniform movement of the packer head and shaft.

2. In a concrete pipe machine, the combination with a rotative packer shaft and packer head, a beam engaged therewith at its forward end and fulcrumed at its rear end, a rotative element, a crank engaged wit-h said rotative' element and with the beam for imparting up and down movement to the beam, a double time rotative element driven from the first named rotative element and connections actuated by said double time element for shifting the fulcrum of the beam in such manner as to maintain a uniform movement of the packer shaft.

3. The combination with a concrete pipe machine comprising a rotati've packer shaft and'packer head,,of a beam engaged with the packer shaft at its forward end and fulcrumed at its rear end, a rotative element, a crank connecting said element with the beam for inn aarting up and down movement to the learn from the rotative element, a shaft upon which the rotative element is located a double time shaft, means for driving the double time shaft from the first named shaft, an

eccentric carried by the double time shaft,

a movable guide link engaged by said eccentric, a pivot carried by the guide link and constituting the fulcrum point for the beam.

In testimony whereof I affix my signature.

CHARLES P. STEWART. I 

